public class ShapeFactory {
    public Shape getShape(String shapeType) {
        if ( shapeType == null ) return null;

        if ( shapeType.equalsIgnoreCase("CIRCLE") ) {
            return new Circle();
        } else if ( shapeType.equalsIgnoreCase("RECTANGLE") ) {
            return new Rectangle();
        } else if ( shapeType.equalsIgnoreCase("SQUARE") ) {
            return new Square();
        }

        return null;
    }
}
